Vertical suspended centrifugal pump

ABSTRACT

The present invention comprises a vertical suspended centrifugal pump. It is particularly useful to pump process liquids having high purity requirements or for outdoor applications in cold environments. The invention comprises a column that is an outer housing, an internal column that is an inner housing, and a shaft assembly that is partially located inside the inner housing. The outer housing encloses some part of the shaft assembly and at least partially encloses the inner housing. A wet end assembly is positioned to receive liquid through an inlet and to discharge liquid through an outlet. The present invention may be configured to include an internal barrier or buffer liquid reservoir without expensive external piping and reservoirs for pumps having two seals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalApplication Ser. 62/439,678 filed Dec. 28, 2016.

STATEMENT REGARDING FEDERALLY FUNDED RESEARCH

Not Applicable

FIELD OF INVENTION

The present invention relates to vertical suspended centrifugal pumps.More particularly, the invention relates to vertical suspended pumpsthat have seals and reservoirs.

BACKGROUND

Vertical suspended pumps are used in multiple industries to transferliquid medium for collection, raw material extraction, to generatepower, and for industrial processes. For example, vertical suspendedpumps, described in the prior art, have been used in hydraulicapplications in which fluid medium must be pumped from undergroundtanks, pits, sumps or similar repositories. Such pumps have housings orcolumns that create an internal space to control hydraulic forces.Rotors in such pumps are vertically oriented having shafts that transferaxial and torsional forces and loads during the pumping process.Torsional loads are often produced from a motor that drives the shaftradially to move or spin impellers that create a force differential topull the liquid medium upwards, vertically, from the repository. Axialloads are produced from the hydraulic forces of the moving liquidmedium. Bearings are used to reduce friction and facilitate smoothradial movement of the shaft and impeller components. Tensile loads aregenerated through the movement of the liquid medium upwards through theshaft and columns or casings that maintain the vacuum and flow of theliquid medium. Various seals may be employed to contain the liquidmedium in the column in which the liquid medium is transferred againstopposing hydraulic forces generated during the pumping process. Thebearings also impart stability of movement of the shaft components.Tensile loads are also generated between the impeller and the bearings.

In a common set up, the vertical suspended pump is comprised of a motorassembly that is fixedly attached to a mounting plate, the shaftassembly is located inside the column also known as a housing or casing.The casing may be a single casing, axial-flow with discharge through thecolumn, single casing, volute, line-shaft driven or cantilever,double-casing, or diffuser.

Axial or mechanical seals may be used in a single seal system thatemploys grease or lubricant on the seals or bearings. In addition, thereare applications where a dual wet pumping seal is used to containprocess fluid or liquid medium. For example, axial seals are used inindustrial settings to prevent internal pump component deteriorationfrom pumped corrosive, abrasive, or toxic liquid medium. There is a needin the art to prevent or contain contamination of the pumped processfluid, with bearing material or lubricant or from contact with sealbuffer liquid or barrier liquid, when there is failure of the wet endseals.

An example in which minute contamination can destroy the product to bepumped is Diesel Exhaust Fluid (further referred to as DEF). DEF is astandardized product that is also known as AUS32. DEF is an aqueous ureasolution that is used for selective catalytic reduction (SCR) of dieselexhaust from diesel burning engines to reduce nitrogen oxide emissions.The DEF is normally pumped from underground reservoirs into containersor dispensing machines for use in diesel engines. The InternationalOrganization for Standards (ISO) quality standards for DEF are tightlyspecified. In order to meet ISO standards for DEF, any surfaces indirect contact with DEF must be free from foreign matter such as fuel,oil, greases, and any other chemicals or natural products. A minuteamount of oil from a single or double seal pumping system can completelycontaminate an entire DEF reservoir.

Two widely used pumps that are used to pump DEF in commercial retailsettings are a submersible turbine pump and a vertical suspended pump.Neither the submersible turbine pump nor the vertical suspended pumpreadily meet ISO requirements and are not well suited for theapplication.

Submersible pumps normally are equipped with a motor that is air filledor oil filled and is sealed from the pump wet end by double seals withan oil chamber between the seals. Currently available submersible pumps,that can detect seal failure, utilize a seal leak conductivity probelocated in the sealed oil chamber. However, because the seal leakconductivity probe is located in the sealed oil chamber, it will notdetect the presence of leaking pumped process fluid optimally. Detectionof seal breach will not occur until the pumped process fluid has enteredthe sealed chamber and both the oil in the sealed chamber and the pumpedprocess liquid are cross-contaminated. Therefore, there is a need in theart to obtain the earliest possible leak detection to preventsignificant contamination of the seal buffer liquid or the pumpedprocess fluid.

Submersible pumps that use oil lubricated and oil prefilled motors alsocan cause contamination of DEF or other pumping fluids if there isfailure of the double seals in the pump.

In vertical suspended pumps with axial flow discharge through thecolumn, an enclosed shaft line column with bearings and lubricant isused. The shaft line column is sealed from the pumping fluid by amechanical seal and positioned inside the column. The drawback of thisdesign is the total absence of, or the complexity of, a leak detectionsystem. If the mechanical seal fails, the pump will continue to pump theprocess fluid without detecting the seal failure. This will allow thepumped process fluid to enter the shaft column. The pumped process fluidcan therefore react or corrode the lubricant, bearings and pumpcomponents. Inversely, the bearings and their lubricant can contaminatethe pumped process fluid if there is seal failure.

Also, there are different vertical suspended pumps with shaft sealingsystem that requires using an external reservoir for seal buffer orbarrier fluid. For example, vertical suspended pumps may employ pipingsystems with reservoirs with two liquid seals. The proper operation isonly achieved with exclusion of all gas and air bubbles from the piping.Venting of such piping systems during use is critical. In addition,often the price of such piping systems doubles the purchase price andmaintenance of the pump. In areas with extremely low wintertemperatures, maintaining shaft sealing systems with the externalreservoir also requires additional efforts and expenditures.

Suspended centrifugal pumps that are used in chemical, oil and gasindustries include configurations where the discharge pipe is separatedfrom the shaft line and shaft guided by the bearings with variouslubrication options, for example, by the pumped fluid, external flush,grease, or oil. The line shaft column is sealed from the wet end by thesingle or double seals. In all of the above configurations, there existsthe potential for pumping fluid contamination, because the pumping fluidis either in direct contact with the shaft bearings or in contact withseal buffer or barrier liquid if there is seal failure.

Therefore, a need exists in the suspended pump field to address theissues of pumping fluid contamination and detection of seal failurebefore the contamination of the pumping fluid occurs. This is achievedin the present invention. In addition, a need also exists to easily andinexpensively maintain the internal conditions and temperature of thepump and the pumped buffer liquid in harsh environments. The presentinvention also provides improvements in the means to control internalpump conditions by incorporating an internal reservoir.

BRIEF SUMMARY OF THE INVENTION

The present invention is a vertical suspended centrifugal pumpcomprising a column assembly, consisting of at least an outer housing,an outer housing cavity, an inner housing, and an inner housing cavity.The present invention also has a rotatable shaft, where the shaft isenclosed partially within the inner housing. The inner housing isenclosed at least partially within the outer housing, the inner housingcavity, and the outer housing cavity, are isolated from each other. Aprobe, sensor, or switch may optionally be used to detect a breach ofthe various isolated cavities by a pumped process liquid or by liquidcontamination from the upper sections of the housing or from the innerhousing cavity. For example, water or other liquids from the externalenvironment may enter the outer housing cavity.

The present invention may employ a motor assembly located outside of astorage tank from which a liquid medium is contained that is to bepumped. The motor assembly can be mounted in different positions to abase plate by various mounts or other components. The total length ofthe column assembly can vary depending on the need of the customer orother application requirements. It can also be configured as a singlesection or as a multi-sectioned column. The present invention also has awet end assembly that includes a casing assembly, one or more impellersand wet end seal that can be made out of various materials in variousshapes. The outer housing cavity may optionally be sealed to maintainthe required isolation of internal cavities. The seals are createdbetween the inner housing and outer housing and have a geometry thatallows at least a portion of the shaft to be exposed directly to theouter housing cavity. The exposed portion of the shaft is a line shaftassembly that lies below the inner housing assembly and above a wet end.The sensors or switches may optionally be installed in the outer housingcavity. A discharge pipe that is separate from the column assembly runsfrom the casing assembly and may optionally be connected to orpositioned through the base plate. The base plate, optionally, issealed. It is contemplated that there also will be one or more dischargeports to connect the casing assembly with the external piping or withthe other equipment. The discharge ports may be formed in differentshapes and configurations such as a threaded connection, flangedconnection, or other means to allow connection to the casing assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross sectional view of one example of the verticalsuspended centrifugal pump assembly with a dry outer housing cavityaccording to various embodiments described herein.

FIG. 2 illustrates a cross sectional view of one example of the verticalsuspended centrifugal pump assembly with a reduced outer housing lengthaccording to various embodiments described herein.

FIG. 3 illustrates a cross sectional view of one example of the verticalsuspended centrifugal pump assembly with an outer housing cavity that isprefilled with a liquid according to various embodiments describedherein.

DETAILED DESCRIPTION OF THE INVENTION

The descriptions and terminology used herein are intended to beillustrative of the principles of the present invention of a verticalsuspended centrifugal pump and are not intended to be limiting. Unlessotherwise defined, all terms, including technical and scientific terms,used herein have the same meaning as commonly understood by one havingordinary skill in the art to which the present invention belongs. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure and will not be interpreted in an idealized or overlyformal sense unless expressly so defined herein.

One of skill in the art will recognize and understand that there aresuitable modifications and equivalents that may be used which fallwithin the scope of the invention described herein. The use of singularforms “a,” “an,” and “the” include plural references unless the contextclearly requires otherwise. The embodiments are not limited to thoseillustrated in the drawings. It should also be understood that thedrawings are not necessarily to scale. In certain instances, details mayhave been omitted that are not necessary for an understanding of theembodiments disclosed herein, for example, conventional fabrication andassembly.

In describing the invention, it will be understood that a number oftechniques and steps are disclosed. Each of these has individual benefitand each can also be used in conjunction with one or more, or in somecases all, of the other disclosed techniques. Accordingly, for the sakeof clarity, this description will refrain from repeating every possiblecombination of the individual steps in an unnecessary fashion.Nevertheless, the specification and claims should be read with theunderstanding that various combinations are entirely within the scope ofthe invention and the claims.

In one embodiment, the vertical suspended centrifugal pump comprises, anouter housing that defines an outer housing cavity, an inner housing,that defines an inner housing cavity, a rotatable shaft, where the shaftis enclosed partially within the inner housing, the inner housing, beingenclosed partially within the outer housing, the inner housing cavity,and the outer housing cavity, being isolated from each other. The termisolated is meant to describe that the inner housing cavity, and theouter housing cavity, are not in fluid or open communication with eachother and are intended to have the space defined in each cavity to beseparately maintained and isolated from other cavity spaces in theoperation of the present invention. In this embodiment, the presentinvention, also comprises a sensor, the senor is capable of detectingthe presence or absence of a liquid within the outer housing cavity.

In one embodiment the vertical suspended centrifugal pump of the presentinvention comprises an outer housing that defines an outer housingcavity, an inner housing that defines an inner housing cavity, arotatable shaft, and a wet end seal. The shaft is enclosed partiallywithin the inner housing, the inner housing is enclosed partially withinthe outer housing, the inner housing cavity and the outer housing cavityare isolated from each other, wherein a portion of the shaftcommunicates with the outer housing cavity below the inner housingcavity and above the wet end seal. The embodiment herein describedcontains at least one sensor, the at least one sensor is capable ofdetecting the presence or absence of a liquid within the outer housingcavity.

Referring to FIG. 1, the pump of the present invention is illustratedand may be driven by at least one motor assembly 10 connected by meanssuch as a direct drive, belt, or coupling means, 148, to a shaft orshaft assembly, 116, which shaft assembly, 116, transfers torque. Theshaft assembly 116 can be comprised in one or more sections. The motorassembly, 10, can be mounted firmly on to a base plate, 112, eitherdirectly or via other means such as a mount, 44.

It should be noted that the base plate is an optional element and thepresent invention may be stabilized by the base plate or by other means.

Referring to FIG. 1, the vertical suspended centrifugal pump of thepresent invention, 100, comprises an outer housing, 118, the outerhousing, 118, is a column, wherein the column is formed of at least onesection. The outer housing, 118, has an upper end and a lower end. Thisembodiment further comprises an inner housing, 114, wherein the innerhousing, 114, is a column. The column is formed of at least one sectionthat has an upper end and a lower end. The inner housing, 114, furtherdefines an inner housing cavity, 130. The present invention, 100, asshown in the embodiment of FIG. 1, also may have a pump casing assembly,120, that is formed of at least one section, the pump casing assembly,120, is positioned at the lower end of the outer housing, 118, whereinthe boundary surfaces of the outer housing, 118, the inner housing, 114,the pump casing assembly, 120, and optionally the base plate, 112, aremated and define the boundaries of an outer housing cavity, 128. Ifthere is no base plate incorporated, then the upper end of the outerhousing will replace the base plate as one of the boundary surfaces thatdefines the outer housing cavity. It should also be noted that the outerhousing may be connected either directly to the base plate or via anintermediary connecting device or element and will depend on theapplication. This embodiment comprises the inner housing, 114, beingenclosed within the outer housing cavity, 128. The present invention,100, further comprises a pump lower end cap, 119, which defines a voidthat is isolated from the outer housing cavity, 128. The pump lower endcap, 119, further defines an inlet, 121, and an outlet, 123. The presentinvention, 100, further comprises a shaft, 116, that has an upper end, alower end, and a vertical axis, wherein the shaft, 116, is rotatableabout its vertical axis. This embodiment also has at least two bearings,152, wherein the at least two bearings, 152, radially surrounding theshaft, 116, the at least two bearings, 152, are rotatable with respectto one another, and the bearings, 152, are further positioned within theinner housing, 114. The present invention, 100, also has at least oneimpeller assembly, 122, alternatively known as an impeller. Theimpeller, 122, is fixedly attached to the lower end of the shaft, 116,and is also positioned within the void of the pump lower end cap, 119.It is an intention of the present invention that the impeller, 122, isrotatable so that the rotation produces force to drive fluid from theinlet, 121, to the outlet, 123. The embodiment, as illustrated in FIG.1, also has at least one probe or sensor, 132, capable of detecting thepresence or absence of a liquid within the outer housing cavity, 128.

In the embodiment, illustrated in FIG. 1, the vertical suspendedcentrifugal pump of the present invention, 100, the outer housing, 118,is sealed.

Optionally, the bearings of the present invention are lubricated.

In the present invention, as illustrated in FIG. 1, the verticalsuspended centrifugal pump of the present invention, 100, furthercomprises a top shaft seal, 138, wherein the top shaft seal, 138, ispositioned at the upper end of the shaft, 116. The present inventionfurther comprises an outer seal, 136, wherein the outer seal, 136, ispositioned at the lower end of the shaft, 116, and a wet end seal, 134,wherein the wet end seal, 134, is positioned at the lower end of theshaft assembly, 116, and vertically below the outer seal, 136, whereinthe top shaft seal, 138, and the outer seal, 136, serve to isolate theinner housing cavity, 130, from the outer housing cavity, 128, and fromleaks that may occur outside of a reservoir, above the base plate 112.The wet end seal, 134, serves to isolate the void of the pump lower endcap, 119, from the outer housing cavity, 128.

As illustrated in FIG. 1, in order to facilitate optimal detection ofcontamination, the present invention has at least a portion of theshaft, 116, that lies between the wet end seal, 134, and the outer seal,136, exposed to the outer housing cavity, 128.

In the embodiment illustrated in FIG. 1, the vertical suspendedcentrifugal pump further comprises a mount, 144, defining a mountcavity, 145. The mount, 144, has an upper section and a lower section,wherein the mount, 144, is fixedly attached to the base plate, 112, andthe base plate, 112, is fixedly attached to the outer housing, 118. Thevertical suspended centrifugal pump of the present invention, 100, canfurther comprise a motor assembly, 10, wherein the motor assembly, 10,is attached to the shaft, 116, by a coupling means, 148, in order totransfer force axially in order to rotate the shaft, 116, about itsvertical axis.

In one embodiment, the outer housing, 118, is fixedly attached to thebase plate, 112.

Referring again to FIG. 1, the vertical suspended centrifugal pump ofthe present invention, 100, further comprises a discharge pipe, 124,which has a discharge pipe inlet, 125, the discharge pipe inlet, 125, isconnected to the outlet, 123, of the pump lower end cap, 119, and adischarge port, 126, for pumped liquid to exit.

FIG. 2 illustrates an additional embodiment of the present invention ofa vertical suspended centrifugal pump, 200, comprising, an outerhousing, 218, the outer housing, 218, is a column, wherein the column isformed of at least one section. The outer housing, 218, has an upper endand a lower end. A pump casing assembly, 220, is formed of at least onesection, the pump casing assembly, 220, is positioned at the lower endof the outer housing, 218. An inner housing, 214, the inner housing,214, may be a column, wherein the column is formed of at least onesection, the inner housing, 214, defines an inner housing cavity, 230,the inner housing, 214, has an upper end and a lower end. Wherein theouter housing, 218, the inner housing, 214, the pump casing assembly,220, and optionally, the base plate, 212, are mated and define theboundaries of an outer housing cavity, 228. Wherein the inner housing,214, is partially enclosed within the outer housing cavity, 228, and theouter housing, 218, is fixedly attached to the inner housing, 214. Ifthere is no base plate incorporated, then the upper end of the outerhousing will replace the base plate as one of the boundary surfaces thatdefines the outer housing cavity. It should also be noted that the outerhousing may be connected either directly to the base plate or via anintermediary connecting device or element and will depend on theapplication. There is also a pump lower end cap, 219, that defines avoid which is isolated from the outer housing cavity, 228, the pumplower end cap, 219, further defines an inlet, 221, and outlet, 223. Theembodiment also comprises a shaft, 216, having an upper end, a lowerend, and a vertical axis, the shaft, 216, is rotatable about itsvertical axis, wherein the shaft, 216, is partially enclosed within theinner housing, 214.

The embodiment illustrated in FIG. 2 also comprises at least twobearings, 252, radially surrounding the shaft, 216, the shaft, 216, andthe at least two bearings, 252, being rotatable with respect to oneanother, and the at least two bearings, 252, are located within theinner housing, 214. This embodiment also comprises at least oneimpeller, 222, wherein the impeller, 222, is fixedly attached to thelower end of the shaft, 216, and positioned within the void of the pumplower end cap, 219. The impeller, 222, is rotatable, and the rotationproduces force to drive fluid from the inlet, 221, to the outlet, 223.This embodiment comprises a top shaft seal, alternatively called a topshaft seal assembly, 238, the top shaft seal, 238, is positioned at theupper end of the shaft, 216, an outer seal, 236, the outer seal, 236, ispositioned at the lower end of the shaft, 216, and a wet end seal, 234.The wet end seal, 234, is positioned at the lower end of the shaftassembly, 216, and vertically below the outer seal, 236, wherein the topshaft seal, 238, the outer seal, 236, and the wet end seal, 234, serveto isolate the voids of the inner housing cavity, 230, the outer housingcavity, 228, and the void of the pump lower end cap, 219. The embodimentillustrated in FIG. 2 also comprises at least one probe or sensor, 232,wherein the sensor is capable of detecting the presence or absence of aliquid within the outer housing cavity 230. FIG. 2 further illustratesthat at least a portion of the shaft, 216, that lies between the wet endseal, 234, and the outer seal, 236, is exposed to the outer housingcavity, 228. This configuration facilitates contamination detection.

In the embodiment, illustrated in FIG. 2, the vertical suspendedcentrifugal pump of the present invention, 200, further comprises a baseplate, 212. The base plate serves to stabilize the present invention.FIG. 2 further illustrates a motor assembly, 10, wherein the motorassembly, 10, is attached to the shaft, 216, by a coupling means, 248,in order to transfer force axially to rotate the shaft, 216, about itsvertical axis. FIG. 2 illustrates an embodiment further comprising amount, 244, that defines a mount cavity, 245, wherein the mount, 244,has an upper section and a lower section and wherein the mount, 244 isattached to the motor assembly, 10. In this embodiment, the mount, 244,is fixedly attached to the base plate, 212, and the inner housing, 214,is fixedly attached to the base plate, 212. FIG. 2 further illustratesthe outer housing, 218, fixedly attached to the inner housing 214 and tothe casing assembly 220.

The embodiment in FIG. 2 further comprises a discharge pipe, 224, thathas a discharge pipe inlet, 225, the discharge pipe inlet, 225, isconnected to the outlet, 223, of the pump lower end cap, 219, and adischarge port, 226, for pumped liquid to exit.

FIG. 3 illustrates a vertical suspended centrifugal pump of the presentinvention, 300, comprising: an outer housing, 318, wherein the outerhousing, 318, may be a column, the column is formed of at least onesection, the outer housing, 318, has an upper end and a lower end, apump casing assembly, 320, that is formed of at least one section, thepump casing assembly, 320, is positioned at the lower end of the outerhousing, 318. An inner housing, 314, the inner housing, 314, is acolumn, the column being formed of at least one section, the innerhousing, 314, defines an inner housing cavity, 330, the inner housing,314, has an upper end and a lower end. Wherein the outer housing, 318,the inner housing, 314, the pump casing assembly, 320, and optionallythe base plate, 312, are mated and define an outer housing cavity, 328,wherein the inner housing, 314, is at least partially enclosed withinthe outer housing cavity, 328. If there is no base plate incorporated,then the upper end of the outer housing will replace the base plate asone of the boundary surfaces that defines the outer housing cavity. Itshould also be noted that the outer housing may be connected eitherdirectly to the base plate or via an intermediary connecting device orelement and will depend on the application.

The embodiment illustrated in FIG. 3 further comprises a pump lower endcap, 319, that defines a void that is isolated from the outer housingcavity, 328, the pump lower end cap, 319, further defines an inlet, 321,and an outlet, 323, a shaft or shaft assembly, 316, having an upper end,a lower end, and a vertical axis, wherein the shaft is rotatable aboutits vertical axis, at least two bearings, 352, radially surrounding theshaft, 316. The shaft, 316, and the at least two bearings, 352, arerotatable with respect to one another and the at least two bearings,352, are positioned within the inner housing, 314. The embodimentillustrated in FIG. 3 further comprises at least one impeller orimpeller assembly, 322, the impeller, 322, is fixedly attached to thelower end of the shaft, 316, and positioned within the void of the pumplower end cap, 319. The impeller, 322, is rotatable, wherein therotation produces force to drive fluid from the inlet, 321, to theoutlet, 323. A top shaft seal, 338, the top shaft seal, 338, ispositioned at the upper end of the shaft, 316, an outer seal, 336, theouter seal, 336, is positioned at the lower end of the shaft, 316, and awet end seal, 334, the wet end seal, 334, is positioned at the lower endof the shaft assembly, 316, and vertically below the outer seal, 336,wherein the top shaft seal, 338, the outer seal, 336, and the wet endseal, 334, serve to isolate the voids of the inner housing cavity, 330,the outer housing cavity, 328, and the void of the pump lower end cap,319. Wherein at least a portion of the shaft, 316, that lies between thewet end seal, 334, and the outer seal, 336, is exposed to the outerhousing cavity, 328. The embodiment is intended to be operated with adesired liquid, 340, that at least partially fills the outer housingcavity, 328, wherein the outer housing cavity, 328, serves as aninternal barrier or buffer in order to provide a barrier or bufferliquid. The barrier liquid provides an alternative means to preventcontamination of the pumped liquid or process fluid. The barrier liquidmay be pressurized by air or other means to enhance the barrier effect.

In another embodiment, as illustrated in FIG. 3, the vertical suspendedcentrifugal pump of the present invention, 300, may be configured,optionally, so that the outer housing cavity, 328, further comprises atleast one liquid port, 342, through which a means to add, remove, orcirculate the desired liquid, 340 may be employed.

In another embodiment, as illustrated in FIG. 3, the vertical suspendedcentrifugal pump of the present invention, 300, optionally provides forthe desired liquid to be circulated by an internal or externalcirculation device. Optionally, the present invention, 300, may includethe liquid port, 342, a circulation device, 350, or both, to provide ameans to circulate liquid within the outer housing cavity, 328.

In another embodiment, as illustrated in FIG. 3, the vertical suspendedcentrifugal pump of the present invention, 300, further comprises thatthe outer housing cavity, 328, may be pressurized in order to provide aseal barrier liquid between the wet end seal, 334, and the outer seal,336.

In another embodiment, the vertical suspended centrifugal pump of thepresent invention, 300, the outer housing cavity, 328, is notpressurized.

Referring again to FIG. 3, in the embodiment illustrated therein, thevertical suspended centrifugal pump of the present invention, 300,further comprises a base plate, 312, on which the outer housing, 318, isfixedly attached. Optionally, the outer housing, 318, may be attached tothe base plate, 312, through an intermediary connector or means whichserves as a bridging means between the outer housing, 318, and the baseplate, 312.

In another alternative embodiment, as illustrated in FIG. 3, thevertical suspended centrifugal pump of the present invention, 300,further comprises a mount, 344, which defines a mount cavity, 345, themount, 344, has an upper section and a lower section, wherein the mount,344, is fixedly attached-to the base plate, 312.

In one embodiment, as illustrated in FIG. 3, the vertical suspendedcentrifugal pump of the present invention, 300, further comprises amotor assembly, 10, wherein the motor assembly, 10, is attached to theshaft, 316, by a coupling means, 348, in order to transfer force axiallyin order to rotate the shaft, 316, about its vertical axis.

In another embodiment, as illustrated in FIG. 3, the vertical suspendedcentrifugal pump of the present invention, 300, further comprises adischarge pipe, 324, having a discharge pipe inlet, 325, the dischargepipe inlet, 325, is connected to the outlet, 323, of the pump lower endcap, 319, and a discharge port, 326, for pumped liquid to exit.

In one embodiment, the motor is connected to the shaft by a connectionmeans that can consists of a coupling made of a rigid or semi-rigidmaterial, a belt, or other type of connection that will allow transferof axial rotation forces from the motor to the shaft.

In one embodiment, the mount is a flange, brackets, collars, or similarmounting system.

The at least two bearings within the inner housing cavity are intendedto mate, facilitate, and stabilize rotational movement of the shaftassembly within the inner housing during operation of the presentinvention.

In one embodiment, the inner housing cavity is sealed.

In another embodiment, the inner housing cavity is not sealed.

As the application needs require, the outer housing can be configured indifferent lengths. The outer housing cavity is isolated from the pumpedprocess fluid by the wet end seal. The outer housing alternatively canextend from the pump casing assembly to the base plate, run through thebase plate, or can extend from the pump casing assembly and be sealedagainst the inner housing.

The outer housing cavity, optionally, may be sealed. At least a portionof the outer housing cavity is exposed to the shaft assembly below theinner housing and above the wet end seal. The outer housing cavityalternatively may be dry or prefilled with the seal buffer liquid orbarrier liquid.

Single or multiple probes, sensors, or switches may be installed insidethe outer housing cavity.

It is intended that one or multiple impellers are employed in thepresent invention and located inside the pump casing assembly.

The discharge pipe may be attached to the base plate or, alternatively,run through it. The connection between the base plate and the dischargepipe optionally may be sealed. Alternatively, the discharge port may belocated on or above the base plate.

Optionally, the inner housing cavity may be sealed between the top shaftseal and the outer seal in order to prevent liquids from uncontrollablyentering or exiting the inner housing cavity.

The at least two bearings optionally may be lubricated depending on thechoice of the bearings. The outer housing cavity, if left dry, is usedas a chamber for detecting and collecting any substances that may leakfrom the wet end seal or any other leakage into the outer housingcavity. Detection of such leakage may be facilitated by a sensor, probe,float switch or any combination thereof. It is intended that leakedmaterial will be detected by the invention prior to impact of the leakedmaterial to any component inside the inner cavity or the pumping fluid.In this manner, the outer housing cavity in combination with the sensorsor probes allows the user to detect leakage and stop pump operationafter wet end seal failure or other seal failures and before pumpedprocess fluid or the inner housing cavity are contaminated. This canprevent pumped process fluid contamination by the bearing lubricant orby the other materials inside the inner housing cavity or corrosion ofpump internal elements.

In one embodiment, if the outer housing cavity is prefilled with thedesired liquid as a seal buffer liquid or barrier liquid reservoir thenthe present invention is not intended to include liquid ports. In thatembodiment, the prefilled outer housing cavity eliminates the need foran external reservoir and piping for the seal buffer liquid or barrierliquid. This solution significantly reduces the cost of the axillaryequipment, increases reliability, and simplifies service.

In one embodiment, the at least one liquid port is contemplated to beincluded in the present invention in order to facilitate liquid filling,venting, a pressure source, draining, cooling, instrumentation, or othermeans to circulate or monitor the desired liquid that serves as a sealbuffer or barrier liquid within the outer housing cavity. The sealbuffer liquid or barrier liquid may be circulated in order to flush theouter seal by means of an optional internal circulating device or viathe optional external circulation system through the at least one liquidport. The at least one probe or sensor optionally may be installedinside the outer housing cavity. This embodiment is effective in pumpswith with a two seal configuration.

Piping losses may be minimized through the correct selection of pipesize, elimination of fittings, use of large radius bends, and reductionin the length of piping runs. All of these requirements often conflictwith each other and hard to implement in long vertical suspended pumps.Additionally, proper operation is achieved with exclusion of all gas andair bubbles from the piping. Venting of a system during thecommissioning of the pump is critical. Very often the price of suchvertical piping systems is close to the price of the pump itself. Inoutdoor applications, especially in areas with extremely low wintertemperatures. There is a high cost to keep such pumps running by usingexternal reservoirs to maintain the internal temperature of the pump.The present invention is intended to minimize those requirements.

Optionally, in one embodiment, the present invention may have two seals.The outer housing cavity may optionally be filled by the seal bufferliquid or barrier liquid.

Optionally an external reservoir and piping may be employed with thepresent invention for the seal buffer liquid or barrier liquid.

Optionally, the seal buffer liquid or barrier liquid reservoir mayinclude an internal or external circulation device.

While some of the preferred materials for elements have been described,the pump is not limited by these materials. Thermoplastic polymers,rubber, foam, metal alloys, aluminum, and other materials may comprisesome or all of the elements of the pump and apparatuses in variousembodiments of the present invention. Some of the elements of thepresent invention may need to be fabricated de novo based on theapplications and sizes required for the applications.

Some of the elements for the present invention may be obtained fromcommercial suppliers. Example suppliers for some elements of the presentinvention follow. Pump electric motors may be obtained from BaldorMotors, 9810 Industrial Blvd, Lenexa, Kans., 66215. Discharge pipes thatare 2 inch diameter 316 stainless steel may be obtained from US METAL,19102 Gundle Road, Houston Tex., 77073. Discharge ports that are 316stainless steel may also be obtained from US METAL. Liquid sensors, forexample, a stainless steel float level switch with ¼″ NPT stem, modelM5600, may be obtained from Madison Company, 27 Business Park Drive,Branford, Conn. 06405. Mechanical seals, for example, a John Crane Type21 seal, may be obtained from John Crane Inc., 2931 East Apache Street,Tulsa Okla. 74110. Single lip seals may be obtained from Garlock, 628 NWPlatte Valley Drive, Riverside, Mo., 64150. Stainless steel 0.5 inchdiameter tubing may be obtained from US METAL, 19102 Gundle Road,Houston Tex., 77073. Flexible couplings 1 inch diameter may be obtainedfrom Lovejoy at Bearing Headquarters 3010 South 2th Street, Kansas City,Kans., 66106.

Although the present invention has been illustrated and describedherein, it will be readily apparent to those of ordinary skill in theart that other embodiments and examples may perform similar functions orachieve like results. All such equivalent embodiments and examples arewithin the spirit and scope of the present invention, are contemplatedthereby.

We claim:
 1. A vertical suspended centrifugal pump comprising: an outerhousing defining an outer housing cavity, an inner housing defining aninner housing cavity, a rotatable shaft, a wet end seal, the shaft beingenclosed partially within the inner housing, the inner housing being atleast partially enclosed within the outer housing, the inner housingcavity and the outer housing cavity being isolated from each other,wherein a portion of the shaft communicates with the outer housingcavity below the inner housing cavity and above the wet end seal, and atleast one sensor, the at least one sensor being capable of detecting thepresence or absence of a liquid within the outer housing cavity.
 2. Avertical suspended centrifugal pump comprising: an outer housing, theouter housing being a column, the column being formed of at least onesection, the outer housing having an upper end and a lower end, a pumpcasing assembly being formed of at least one section, the pump casingassembly being positioned at the lower end of the outer housing, a pumplower end cap defining a void that is isolated from the outer housingcavity, the pump lower end cap further defining an inlet and an outlet,a shaft having an upper end, a lower end, and a vertical axis, the shaftbeing rotatable about its vertical axis, an inner housing, the innerhousing being a column, the column being formed of at least one section,the inner housing defining an inner housing cavity, the inner housinghaving an upper end and a lower end, wherein the outer housing, theinner housing, and the pump casing assembly are mated and define theboundaries of an outer housing cavity, wherein the inner housing isenclosed within the outer housing cavity, at least two bearings radiallysurrounding the shaft, the shaft and the at least two bearings beingrotatable with respect to one another, the at least two bearings beingwithin the inner housing, at least one impeller, the impeller beingfixedly attached to the lower end of the shaft and positioned within thevoid of the pump lower end cap, the impeller being rotatable, andwherein the rotation produces force to drive fluid from the inlet and tothe outlet, and at least one sensor, the at least one sensor beingcapable of detecting the presence or absence of a liquid within theouter housing cavity.
 3. The vertical suspended centrifugal pump ofclaim 2 wherein the outer housing is sealed.
 4. The vertical suspendedcentrifugal pump of claim 2 wherein the shaft has a top shaft seal, thetop shaft seal being positioned at the upper end of the shaft, an outerseal, the outer seal being positioned at the lower end of the shaft, anda wet end seal, the wet end seal being positioned at the lower end ofthe shaft assembly and vertically below the outer seal, wherein the topshaft seal, the outer seal, the wet end seal serve to isolate the innerhousing cavity, the outer housing cavity, and the void of the pump lowerend cap, and wherein at least portion of the shaft that lies between thewet end seal and outer seal, is exposed to the outer housing cavity. 5.The vertical suspended centrifugal pump of claim 2 further comprising amount, defining a mount cavity, and having an upper section and a lowersection, wherein the mount is fixedly attached to a base plate andwherein the base plate is fixedly attached to the outer housing.
 6. Thevertical suspended centrifugal pump of claim 2 wherein the outerhousing, the inner housing, the pump casing assembly, and the base plateare mated and define the outer housing cavity.
 7. The vertical suspendedcentrifugal pump of claim 2 further comprising a motor assembly whereinthe motor assembly is attached to the shaft by a coupling means in orderto transfer force axially in order to rotate the shaft about itsvertical axis.
 8. The vertical suspended centrifugal pump of claim 2further comprising a base plate to which the outer housing is fixedlyattached.
 9. The vertical suspended centrifugal pump of claim 2 furthercomprising a discharge pipe having a discharge pipe inlet, the dischargepipe inlet being connected to the outlet of the pump lower end cap, anda discharge port for pumped liquid to exit.
 10. A vertical suspendedcentrifugal pump comprising: an outer housing, the outer housing being acolumn, the column being formed of at least one section, the outerhousing having an upper end and a lower end, a pump casing assemblybeing formed of at least one section, the pump casing assembly beingpositioned at the lower end of the outer housing, a pump lower end capdefining a void that is isolated from the outer housing cavity, the pumplower end cap further defining an inlet and an outlet, a shaft having anupper end, a lower end, and a vertical axis, the shaft being rotatableabout its vertical axis, an inner housing, the inner housing being acolumn, the column being formed of at least one section, the innerhousing defining an inner housing cavity, the inner housing having anupper end and a lower end, wherein the shaft is at least partiallyenclosed within the inner housing, wherein the outer housing, the innerhousing, and the pump casing assembly are mated and define theboundaries of an outer housing cavity, wherein the inner housing ispartially enclosed within the outer housing cavity and the outer housingis fixedly attached to the inner housing, at least two bearings radiallysurrounding the shaft, the shaft and the at least two bearings beingrotatable with respect to one another, the at least two bearings beingwithin the inner housing, at least one impeller, the impeller beingfixedly attached to the lower end of the shaft and positioned within thevoid of the lower end cap, the impeller being rotatable, and wherein therotation produces force to drive fluid from the inlet to the outlet, atop shaft seal, the top shaft seal being positioned at the upper end ofthe shaft, an outer seal, the outer seal being positioned at the lowerend of the shaft, and a wet end seal, the wet end seal being positionedat the lower end of the shaft assembly and vertically below the outerseal, wherein the top shaft seal, the outer seal, and the wet end sealserve to isolate the voids of the inner housing cavity, the outerhousing cavity, and the void of the end cap, wherein at least portion ofthe shaft that lies between the wet end seal and outer seal, is exposedto the outer housing cavity, and at least one sensor, the at least onesensor being capable of detecting the presence or absence of a liquidwithin the outer housing cavity.
 11. The vertical suspended centrifugalpump of claim 10 further comprising a base plate to which the innerhousing is fixedly attached.
 12. The vertical suspended centrifugal pumpof claim 10 further comprising a mount, defining a mount cavity, andhaving an upper section and a lower section, wherein the mount isfixedly attached to a base plate and wherein the base plate is fixedlyattached-to the inner housing.
 13. The vertical suspended centrifugalpump of claim 10 further comprising a motor assembly wherein the motorassembly is attached to the shaft by a coupling means in order totransfer force axially to rotate the shaft about its vertical axis. 14.The vertical suspended centrifugal pump of claim 10 further comprising adischarge pipe having an inlet, the inlet connected to the outlet of thepump lower end cap, and a discharge port for pumped liquid to exit. 15.A vertical suspended centrifugal pump comprising: an outer housing, theouter housing being a column, the column being formed of at least onesection, the outer housing having an upper end and a lower end, a pumpcasing assembly being formed of at least one section, the pump casingassembly being positioned at the lower end of the outer housing, a pumplower end cap defining a void that is isolated from the outer housingcavity, the pump lower end cap further defining an inlet and an outlet,a shaft having an upper end, a lower end, and a vertical axis, the shaftbeing rotatable about its vertical axis, an inner housing, the innerhousing being a column, the column being formed of at least one section,the inner housing defining an inner housing cavity, the inner housinghaving an upper end and a lower end, wherein the outer housing, theinner housing, and the pump casing assembly are mated and define theboundaries of an outer housing cavity, wherein the inner housing is atleast partially is enclosed within the outer housing cavity, at leasttwo bearings radially surrounding the shaft, the shaft and the at leasttwo bearings being rotatable with respect to one another, the at leasttwo bearings being within the inner housing, at least one impeller, theimpeller being fixedly attached to the lower end of the shaft andpositioned within the void of the pump lower end cap, the impeller beingrotatable, and wherein the rotation produces force to drive fluid fromthe inlet to the outlet, a top shaft seal, the top shaft seal beingpositioned at the upper end of the shaft, an outer seal, the outer sealbeing positioned at the lower end of the shaft, and a wet end seal, thewet end seal being positioned at the lower end of the shaft assembly andvertically below the outer seal, wherein the top shaft seal, the outerseal, and the wet end seal serve to isolate the voids of the innerhousing cavity, the outer housing cavity, and the void of the end cap,wherein at least portion of the shaft that lies between the wet end sealand outer seal, is exposed to the outer housing cavity, and a desiredliquid, wherein the desired liquid at least partially fills the outerhousing cavity and serves as an internal barrier in order to provide abarrier or buffer liquid, and the outer housing cavity is a liquidreservoir.
 16. The vertical suspended centrifugal pump of claim 15wherein the outer housing cavity further comprises at least one liquidport to facilitate the addition, removal, or circulation of the desiredliquid.
 17. The vertical suspended centrifugal pump of claim 15 furthercomprising at least one sensor to monitor the desired liquid.
 18. Thevertical suspended centrifugal pump of claim 15 wherein the desiredliquid is circulated by an internal or external circulation device. 19.The vertical suspended centrifugal pump of claim 15 wherein the outerhousing cavity is pressurized in order to provide a seal barrier liquidbetween the wet end seal and the outer seal.
 20. The vertical suspendedcentrifugal pump of claim 15 wherein the outer housing cavity is notpressurized.
 21. The vertical suspended centrifugal pump of claim 15further comprising a base plate on which the outer housing is fixedlyattached.
 22. The vertical suspended centrifugal pump of claim 15further comprising a mount, defining a mount cavity, and having an uppersection and a lower section, wherein the mount is fixedly attached to abase plate and wherein the base plate is fixedly attached-to the outerhousing.
 23. The vertical suspended centrifugal pump of claim 15 furthercomprising a motor assembly wherein the motor assembly is attached tothe shaft by a coupling means in order to transfer force axially inorder to rotate the shaft about its vertical axis.
 24. The verticalsuspended centrifugal pump of claim 15 further comprising a dischargepipe having an inlet, the inlet connected to the outlet of the pumplower end cap and a discharge port for pumped liquid to exit.